"We reviewed what could be done next and have identified that there are technologies that could well help the situation in Port Pirie to meet not only economic and social outcomes but also the environmental outcome.

The company ... are very much committed to improving emissions wherever they possibly can and they've also approved of that condition that allows us to change the licence again."

A deadline of March has been set for the company to produce its draft plan.

Investment hopes

SA Premier Jay Weatherill said the environmental guidelines for the lead smelter licence were a welcome move.

He said they would give the Government a clearer path for securing new investment in the plant.

It is estimated Nyrstar will need to spend $350 million to reduce emissions to meet guidelines.

Mr Weatherill said he had spoken this week with federal ministers about securing money for Nyrstar.

"Nyrstar clearly will need to invest in new technology to achieve the objectives set out in the new licensing conditions agreed with the EPA," he said.

"There is no denying the importance of the smelter to Port Pirie and the entire Spencer Gulf region. The town would struggle to survive without it."

Port Pirie Mayor Brenton Vanstone said there was clearly a collaborative approach between the SA Government, the EPA and the company.

"I like to call Port Pirie the Roxby Downs of the mid-north because of its huge state importance and I think the Government and the EPA are very aware of that and there's no doubt that it's a cooperative agreement and I just think there can be some effective changes made in the future," he said.